Quantized hydrodynamic model and the dynamic structure factor for a trapped Bose gas

We quantize the recent hydrodynamic analysis of Stringari for the low-energy collective modes of a trapped Bose gas at $T=0$. This is based on the time-dependent Gross-Pitaevskii equation, but omits the kinetic energy of the density fluctuations. We diagonalize the hydrodynamic Hamiltonian in terms of the normal modes associated with the amplitude and phase of the inhomogeneous Bose order parameter. These normal modes provide a convenient basis for calculating observable quantities. As applications, we calculate the depletion of the condensate at $T=0$ as well as the inelastic light-scattering cross section $S({\bf q},\omega)$ from low-energy condensate fluctuations. The latter involves a sum over all normal modes, with a weight proportional to the square of the ${\bf q}$ Fourier component of the density fluctuation associated with a given mode. Finally, we show how the Thomas-Fermi hydrodynamic description can be derived starting from the coupled Bogoliubov equations.Comment: 25 pages, 4 figures, submitted to Phys. Rev.

Finite temperature hydrodynamic modes of trapped quantum gases

The hydrodynamic equations of an ideal fluid formed by a dilute quantum gas in a parabolic trapping potential are studied analytically and numerically. Due to the appearance of internal modes in the fluid stratified by the trapping potential, the spectrum of low-lying modes is found to be dense in the high-temperature limit, with an infinitely degenerate set of zero-frequency modes. The spectrum for Bose-fluids and Fermi-fluids is obtained and discussed.Comment: 26 pages, Late

Collective excitations of degenerate Fermi gases in anisotropic parabolic traps

The hydrodynamic low-frequency oscillations of highly degenerate Fermi gases trapped in anisotropic harmonic potentials are investigated. Despite the lack of an obvious spatial symmetry the wave-equation turns out to be separable in elliptical coordinates, similar to a corresponding result established earlier for Bose-condensates. This result is used to give the analytical solution of the anisotropic wave equation for the hydrodynamic modes.Comment: 11 pages, Revte

Quantum Kinetic Theory V: Quantum kinetic master equation for mutual interaction of condensate and noncondensate

A detailed quantum kinetic master equation is developed which couples the kinetics of a trapped condensate to the vapor of non-condensed particles. This generalizes previous work which treated the vapor as being undepleted.Comment: RevTeX, 26 pages and 5 eps figure

The role of transglutaminase in the rat subtotal nephrectomy model of renal fibrosis

Tissue transglutaminase is a calcium-dependent enzyme that catalyzes the cross-linking of polypeptide chains, including those of extracellular matrix (ECM) proteins, through the formation of epsilon-(gamma-glutamyl) lysine bonds. This crosslinking leads to the formation of protein polymers that are highly resistant to degradation. As a consequence, the enzyme has been implicated in the deposition of ECM protein in fibrotic diseases such as pulmonary fibrosis and atherosclerosis. In this study, we have investigated the involvement of tissue transglutaminase in the development of kidney fibrosis in adult male Wistar rats submitted to subtotal nephrectomy (SNx). Groups of six rats were killed on days 7, 30, 90, and 120 after SNx. As previously described, these rats developed progressive glomerulosclerosis and tubulo-interstitial fibrosis. The tissue level of epsilon-(gamma-glutamyl) lysine cross-link (as determined by exhaustive proteolytic digestion followed by cation exchange chromatography) increased from 3.47+/- 0.94 (mean+/-SEM) in controls to 13.24+/-1.43 nmol/g protein 90 d after SNx, P </= 0.01. Levels of epsilon-(gamma-glutamyl) lysine cross-link correlated well with the renal fibrosis score throughout the 120 observation days (r = 0.78, P </= 0.01). Tissue homogenates showed no significant change in overall transglutaminase activity (14C putrescine incorporation assay) unless adjusted for the loss of viable tubule cells, when an increase from 5.77+/-0.35 to 13.93+/-4.21 U/mg DNA in cytosolic tissue transglutaminase activity was seen. This increase was supported by Western blot analysis, showing a parallel increase in renal tissue transglutaminase content. Immunohistochemistry demonstrated that this large increase in epsilon-(gamma-glutamyl) lysine cross-link and tissue transglutaminase took place predominantly in the cytoplasm of tubular cells, while immunofluorescence also showed low levels of the epsilon-(gamma-glutamyl) lysine cross-link in the extracellular renal interstitial space. The number of cells showing increases in tissue transglutaminase and its cross-link product, epsilon-(gamma-glutamyl) lysine appeared greater than those showing signs of typical apoptosis as determined by in situ end-labeling. This observed association between tissue transglutaminase, epsilon-(gamma-glutamyl) lysine cross-link, and renal tubulointerstitial scarring in rats submitted to SNx suggests that tissue transglutaminase may play an important role in the development of experimental renal fibrosis and the associated loss of tubule integrity

Dynamics of Charge-Transfer-to-Solvent Precursor States in I-(water)n(n= 3−10) Clusters Studied with Photoelectron Imaging†

The dynamics of charge-transfer-to-solvent states are studied in I-(H2O)n)3-10 clusters and their deuterated counterparts using time-resolved photoelectron imaging. The photoelectron spectra for clusters with n g 5 reveal multiple time scales for dynamics after their electronic excitation. An increase in the vertical detachment energy (VDE) by several hundred millielectronvolts on a time scale of 1 ps is attributed to stabilization of the excess electron, primarily through rearrangement of the solvent molecules, but a contribution to this stabilization from motion of the I atom cannot be ruled out. The VDE drops by 50 meV on a time scale of tens of picoseconds; this is attributed to loss of the neutral iodine atom. Finally, the pump-probe signal decays with a time constant of 60 ps-3 ns, increasing with cluster size. This decay is commensurate with the growth of very slow electrons and is attributed to autodetachment. Smaller clusters (n) 3, 4) display simpler dynamics. Anisotropy parameters are reported for clusters n) 4-9. 1

Holographic Renormalization for z=2 Lifshitz Space-Times from AdS

Lifshitz space-times with critical exponent z=2 can be obtained by dimensional reduction of Schroedinger space-times with critical exponent z=0. The latter space-times are asymptotically AdS solutions of AdS gravity coupled to an axion-dilaton system and can be uplifted to solutions of type IIB supergravity. This basic observation is used to perform holographic renormalization for 4-dimensional asymptotically z=2 locally Lifshitz space-times by Scherk-Schwarz dimensional reduction of the corresponding problem of holographic renormalization for 5-dimensional asymptotically locally AdS space-times coupled to an axion-dilaton system. We can thus define and characterize a 4-dimensional asymptotically locally z=2 Lifshitz space-time in terms of 5-dimensional AdS boundary data. In this setup the 4-dimensional structure of the Fefferman-Graham expansion and the structure of the counterterm action, including the scale anomaly, will be discussed. We find that for asymptotically locally z=2 Lifshitz space-times obtained in this way there are two anomalies each with their own associated nonzero central charge. Both anomalies follow from the Scherk--Schwarz dimensional reduction of the 5-dimensional conformal anomaly of AdS gravity coupled to an axion-dilaton system. Together they make up an action that is of the Horava-Lifshitz type with nonzero potential term for z=2 conformal gravity.Comment: 32 pages, v2: modified discussion of the central charge

Regional Invasive Species & Climate Change Management Challenge: Taking Action. Managing invasive species in the context of climate change

Climate change is likely to alter the timing and effect of invasive species management, as well as the suite of species we are managing. Despite concern about the effects of climate change, lack of information about how and when to take action is a barrier to climate-smart invasive species management. Here, we outline strategies for incorporating climate change into management along with examples of tools that can inform proactive decision-making